Author: MVDr. Dominika Paučová, Kennel Z Podpolianských lúk
HD is a diagnosis that is relevant for both humans and animals. Although it is not so frequent, it occurs also in Japanese spitz breeds. It was described for the first time in the 60s of the last century, and it was with the large dog breeds. With smaller breeds e.g. Shiba it does not come as a huge issue (up to a mild level of dysplasia /C/) because it is small and lightweight dogs. With midsize and large dogs e.g. Shikoku or Akitas, HD becomes a bigger issue due to their weight. The occurrence ratio between males and females is around 50:50.
Individuals are not born with HD - they develop it through their life, it is a disease with polygenic inheritance. However, the particular gene or set of genes that cause HD hereditary transfer to the offsprings has not yet been identified. Hereditary transportability is partly also questioned by empirical breeding experience both in Slovakia and abroad, where parents with excellent hips (HD/A) have also litters not only with HD/A but also HD/B or HD/C }puppies in the same litter) and the other way around - parent with HD/C brings healthy litter with HD/A. The issue is not yet mapped properly - situation is even more complicated because not all individuals are examined for HD and thus we do not have information about HD for all puppies from each litter. Without this information it is not possible to get more informative and better results in this topic.
Joints affected by dysplasia are typically displaying laxity, during a growth phase the joint is developing abnormally and in later advanced stage the joint gets affected by arthrosis.
Due to abnormal development the weight force is not distributed evenly and some parts of the femoral head or socket is overloaded. Articular capsule and ligaments overload cause the cartilage irritation and deterioration, and further imply arthritis and pain. Abnormal joint development in early puppy age (first weeks of life) is usually explained by multiple factors - microtraumas (microinjuries), overload (incorrect surface of birth and living area) overweight, etc.
HEALTHY HIP JOINT
Hip joint is composed of a joint socket acetabulum and femoral head. The head locks together with the socket and surface of both is covered by cartilage that provides joints with flexibility and protection from erosion. In the healthy joint, the femoral head fits very tightly to the socket and thus the load is evenly distributed over the entire surface of both femoral head and the socket.
HD AFFECTED JOINT
Affected individual demonstrates incorrect and shallow fit of femoral head into the socket - head subluxates which causes uneven pressure distribution.The cartilage wears out faster on those specific touch points and it may end up with arthritis or joint luxation. Both subluxation and arthritis are painful for a dog.
IMPORTANT TO KNOW!
Every puppy is born with perfectly healthy hips - from structural and functional perspective. HD develops in time and is caused often by external factors. As a result, the joint starts to develop abnormally which means that the growth plates are closed up too early or are worn out. We have quite interesting information that proves how little we know about HD - siblings from the same litter where both parents had HD/A were raised together - from the very beginning they were kept in the same area, fed the same food, had the same movement and activities. Despite that, they demonstrated different results of HD after being examined after reaching 1 year of age, one of them had HD/A and the other HD/C.
If a dog is diagnosed with hip dysplasia, it is defined as one of five grades (0-4). Healthy specimen has grade 0 (or letter A), the more serious disease is, the higher grades they get (B, C, D, E) while the most serious condition is defined by E grade.
Large and giant breeds suffer the most from hip dysplasia (the German shepherd, Labrador, Newfoundland dog, St. Bernard, etc.) but as we said already, it occurs also with medium and small breeds. Large and giant breeds are impacted the most because they grow rapidly and thus their skeletal framework and joints must deal with a heavy load.
Dysplasia is a multi genetic and multifactorial disease - that means that there is not only one, but a set of genes causing it. The problem is that each breed has a different set of genes which has not yet been identified until now. We still don’t know how big is the role of genetics in developing a HD. Since there are multiple genes, both recessive and dominant ones that cause genetic transfer of this disease, we are not able to confirm whether an individual is a carrier of the HD causing set of genes set or not. Research shows that a dog is not born with the HD, however, it might be born with a predisposition. Whether a dog develops HD of a particular grade is further determined by external factors and that is why we refer to a multifactorial disease.
So, genetics plays its role in the HD. That means it probably matters whether the parents, grandparents, great grandparents etc. suffered from HD. However, based on the lack of data and information, we are not able to analyze in depth and determine which generations affected the HD development down the bloodline. Healthy animals produce also not 100% healthy litters (some resources mention statistics that HD/A parents in general produce around 20% of HD positive puppies).
While trying to eliminate the occurrence of this disease, we come across the issue that HD is strongly affected by the environment, activity, injuries (also bumps and jumps), area for living and nutrition. First 2 months of a puppy's life are crucial for the potential HD development, because the forces of the weight and pressure on the soft and flexible tissues of a hip joint might reach over the limit.
The owner has thus a few options how to affect their dog’s health:
Pick a puppy from a responsible breeder that raises a puppy properly, in good conditions with a proper activity
Avoid trauma from injuries - ensure the puppy has appropriate activities, don’t overload them with extensive exercise up to 1 year of age. Avoid it jumping from elevated places, using stairs, avoid intensive fetching, avoid also slippery surfaces e.g.PVC floors, etc.
Watch out for the weight - overweight is one of the important factors that cause HD as it brings more load to the joints (if you are unsure whether your dog is of a proper weight, consult your vet).
Ensure the proper nourishment - avoid too much calcium intake in combination with vitamin D, lack of vitamins and minerals - inappropriate nutrition in the first year of age can imply huge damage to overall dog’s health. Using cheap and low quality dry kibble or canned food, unbalanced barf diet, feeding table scraps on a regular basis, that all should be avoided especially during the puppy's growth and body development.
Provide the right exercise - avoid jogging or cycling with a dog, long hikes. There will be plenty of time to do that together once your dog reaches full healthy maturity.
Avoid keeping a puppy in a too cold and wet environment
Genetic testing cannot determine whether a dog will be affected by HD or will be a transmitter. Therefore it is a responsible work of breeders that endure their dogs are x-rayed and examined and use the outcomes of these testings responsibly.
Inheritance coefficient is different for each breed, it is between 20-60%, the rest in the breeders’ and owners’ hands.
Proper and appropriate activities (exercise) lead to stable hips and proper development. Lack of it, or the opposite (inappropriate exercise) imply the opposite. Some studies point out risk of intense fetching due to hard stops and sudden changes of direction.
If an owner wants to be sure whether their dog suffers from HD, the dog must undergo an x-ray examination. This examination is taken usually in full anesthesia, the price might vary between 50-100 EUR.
How can you spot that something is not right? The symptoms might not always be visible. Young and muscular individual with mild HD might not even show any signs of it.
Young dogs with subclinical symptoms - owner might spot by coincidence that their dog jumps using its both hind legs (like a rabbit) or by a preventive x-raying (between 4-14 months).
Young dogs demonstrating symptoms - dogs display difficulties when standing up, unwillingness to move, a dog is careful when jumping, it stretches more and does not want to take the stairs or it limps when walking.
Adult dogs (over 12 months) - degenerative changes in the joints, dog lightens the weight on impacted leg, limps even after a small exercise, atrophy of hind leg muscles due to limited movement and arthritis itself.
Conservative - limiting the exercise and weight reduction
Physical - appropriate exercise to strengthen mainly the hip muscles
Medicinal - adding chondroprotective supplements or surgery
HD is not curable. Therapy is also limited, it focuses mainly on softening of symptoms. Anyway, both conservative and surgical treatment is costly and difficult.
Surgery is an option if the HD was diagnosed by coincidence up to 7. month of dog’s life. Once adult, dogs can get the hip joint surgically replaced by a total endoprosthesis or - in case of lighter individuals - they can undergo a femur bone excision.
It is crucial to ensure that a dog with HD gets sufficient amount of appropriate exercise. Appropriate level of the right physical activity that is considerate towards joints and helps dogs to strengthen the particular muscles brings a reasonable benefit.
WHAT SHOULD WE PAY ATTENTION TO?
The age between birth up to 2 months you, as an owner, don’t have the faith of your puppy in your hands. Please, bear the above in mind when considering and selecting the breeder you will take your puppy from. This early life stage is crucial for the future HD potential development! Soft parts of the joint consist of cartilage tissue and can deform and continue to form abnormally. With time, this tissue ossifies and turns into bone tissue. Responsible breeder knows this and pays attention to it. First two months are therefore the most critical time, as all puppies are born with healthy hips.
From the beginning of the 3rd month, when you bring your puppy home, it is in your hands. Pay attention to providing a quality food, in the right daily amounts (not to get your puppy overweight), don’t experiment with different food types without making sure the puppy will get balanced diet with everything it needs. Avoid slippery floors, going up and down the stairs and long walks, jogging or biking with your dog, add exercise continuously until it is fully grown up (at around 1 year).
Between 12-18 months a dog is usually fully grown, however, exercise should be added continuously (don’t take your dog to 30 km hike for his first birthday). If you walk your dog 3x a day for 30 mins each, it should be fine to get him for a hike, but if it is not used to it move more, then really be careful and extend the times and distances slowly. It is similar for people without practice - intense drill is more difficult than enduraning with lower heart beat frequency.
In Slovak breeding, the kennel club requires each Japanese spitz breed individual to have x-ray examination before it is officially approved for breeding. Only specimens with HD/A and HD/B are allowed for breeding.
Photo: MVDr. Dominika Paučová
Author: MVDr. Dominika Paučová
Patella luxation is pretty common disease with polygenic hereditary predisposition that can develop during a dog’s life. It is more common in small breeds e.g. Shiba. While it is in general not very frequent with the Japanese breeds, it occurs from time to time. Out of all health issues typical for Shiba, patella luxation is one of the most frequently occurring ones. It is rare for Akitas.
It is typical with a kneecap (patella) dislocating from its normal anatomic position in the groove of the thigh bone (femur). It is thus related to hind legs, knees in particular. Patella dislocation itself brings more issues - decrease of muscles on entire leg, weakening of the entire knee joint, incorrect anatomy of the knee, deformed limb, etc. These related issues underline the situation and affected dog shows signs of limping, or often develops torn ligaments (a trigger can be a faster turnaround or change of direction). PL can also cause another issue in the future - joint arthritis - since the joint does not move properly and cartilage is getting damaged faster due to unevenly distributed pressure on specific touch points.
Patella luxation can be medial and lateral. Medial luxation means that a kneecap dislocates inside towards the opposite knee, while in lateral luxation kneecap twists outside from the knee. Medial luxation is usually more frequent and often occurs on both knees. Such luxations are less common and occur after a trauma (accidental injury).
PL has a genetic predisposition, therefore future owners shall wisely choose a responsible breeder, a puppy from parents which are tested for PL. In Slovakia, only Shiba individuals with negative luxation (0. grade) or luxation with 1. grade are approved for breeding. However, as we mentioned already, luxation can occur also out of an injury.
0. grade - negative, kneecap firmly fixed in the groove and by mechanic pressing by a hand it does not dislocate
1. grade - kneecap is in the groove, however by pressing on it with hand it can dislocate - after releasing the pressure, it goes back to the groove
2. grade - the same as 1.grade with a difference that after dislocation, the kneecap does not come back itself and stays out of the groove
3. grade - even when palpated, the patella is already out of the groove but can be returned to the groove using a mechanic pressure.
4. grade - same as 3.grade with the difference that the kneecap cannot be returned to the groove even with a mechanic pressure.
Identification of PL is quite simple and pain free. Dog does not need to be in anesthesia, it is done by manual palpation. This examination might be - in serious cases - supplemented by an x-ray.
In case of PL, it is possible to examine a puppy already in its 4 months of age. We recommend testing it even later although you don’t intend your dog for breeding or it comes without a pedigree. If the issue is serious (grade 2 or more), a surgery might be the best solution. The sooner the dog is fixed, the better. When fixed in a later stage of life, surgery brings only partial relief. That is due to already more damaged cartilage and arthritis present already - and even when surgery brings relief, dog might not stop limping. Therefore the surgical solution cannot effectively revert the progress of osteoarthritis and thus what is crucial is early diagnosis and keeping as much as hyaline cartilage as possible during the surgery.
Photo: MVDr. Dominika Paučová